Troubleshoot - Won't start anymore

[Jeepinvusa]

Engine - 77' 1500 (150hp) Merc outboard.

Has been kept in very great shape. Very impressed with the condition for it's year. Bought it with the boat 2months ago. Engine ran rough first time out. Engine sat for a month and was de-carbed (seafoam+gas+mix/1gal) this past Saturday 26Dec. Took her out for a spin and ran perfect on WOT for about 40-45mins... when we arrived at our fishing destination, just happened to completely die (3miles offshore). We anchored. tried to crank again and nothing. Engine turns, starter spins fine... checked the primer bulb and squeezed it till fuel was flowing out... Let her sit for about 30mins and nothing again. I was towed back to the dock. So yesterday I was checking everything. Plugs are new btw from when I de-carbed. Apperently I have no spark. checked with a spark tester and manually while cranking.

Can someone tell me the order how power travels? Going backwards, i understand its plugs are connected to plug wires, then to the coils then to some box that has wires connecting to the coils then that connect to something under the flywheel (like some sort of alternator cause i imagine it creates power by spinning in there....)

Not sure if I did this right, but i tried to check for power from the "box that has wires going to the individual coils" when my brother was cranking with my light tester but nothing... anyhelp!? I would like to take family out and around the bay this weekend...???? please.

 

[Dukedog]

Re: Troubleshoot - Won't start anymore

1500 In-line or V6? Not sure 'bout tha in-line but it might have a safety kill switch (usually has a lanyard but sometimes gets lost) like tha V6. Might have gotten bumped or pulled. Other than that, without a dia. which I don't have, I'm lost. I'm sure someone thats a lot more versed with tha in-line will get on here ta help...............

 

[Jeepinvusa]

Re: Troubleshoot - Won't start anymore

1500 In-line or V6? Not sure 'bout tha in-line but it might have a safety kill switch (usually has a lanyard but sometimes gets lost) like tha V6. Might have gotten bumped or pulled. Other than that, without a dia. which I don't have, I'm lost. I'm sure someone thats a lot more versed with tha in-line will get on here ta help...............

V-6
Would sound correct, but there isn't a lanyard on this dog. hehe. just didn't come with one. There's a switch next to the key but it does absolutely nothing.

 

[Dukedog]

Re: Troubleshoot - Won't start anymore

Toggle or red button? Button should have a rubber type cap with a spring around tha base.........

 

[Dukedog]

Re: Troubleshoot - Won't start anymore

It can be either one. Pull tha switch out. Should have a black/yellow on one side and a black on tha other. Isolate tha black/yellow from tha switch and crank tha motor. If it fires replace tha switch. If not we can look at something else........

 

[Jeepinvusa]

Re: Troubleshoot - Won't start anymore

Thanks dukedog,
Will these wires be on the engine side? Id rather do it form thte engine side and completely eliminate this kill. The switch next to the key is a toggle (up or down). Help me eliminate this completely for now...

 

[Jeepinvusa]

Re: Troubleshoot - Won't start anymore

Thanks dukedog,
Will these wires be on the engine side? Id rather do it form thte engine side and completely eliminate this kill. The switch next to the key is a toggle (up or down). Help me eliminate this completely for now...

 

[Dukedog]

Re: Troubleshoot - Won't start anymore

Not a good thing ta elliminate it. It may/may not be tha problem. But doing the above is just a start at finding tha problem. If you have a 12v test light you can just test tha switch. Ign. switch on. Tha toggle switch will be tha ground side of tha test light. Should make and break on tha black/yellow and be constant on tha black. If ya got real long arms (or some one ta operate tha switch) you can do this at tha switch boxes on tha motor............Just remember your lookin for a ground so constant side of tha test light goes to a 12v positive source.

 

[j_martin]

Re: Troubleshoot - Won't start anymore

Thanks dukedog,
Will these wires be on the engine side? Id rather do it form thte engine side and completely eliminate this kill. The switch next to the key is a toggle (up or down). Help me eliminate this completely for now...

Look at that toggle switch. It is in a guard such that if a loop from a lanyard is put over the switch, and then the switch is put in the up position, the loop cannot be removed without throwing the switch downward. That is the safety kill switch. Up is on, down is kill.

That said, those switches don't like salt. Follow the procedures you've been given and you'll get to a repair.

To run that big an engine without a safety kill lanyard is suicidal.

hope it helps
John

 

[Jeepinvusa]

Re: Troubleshoot - Won't start anymore

thats the odd part, the switch doesn't have any kind of small way of working with a landyard...? why else would there be this toggle next to the key switch... and yes the keyswitch does have a push to choke.

 

[Jeepinvusa]

Re: Troubleshoot - Won't start anymore

another thing, I have playied with this switch while the engine is running so if it is it, then it must have come alive or something... is there any other way to test the coils or the packs?? im going home now so i can check it all...

 

[Dukedog]

Re: Troubleshoot - Won't start anymore

Look on tha control box itself for any kinda switch. Maybe not very noticeable just lookin' at tha box..............

 

[Jeepinvusa]

Re: Troubleshoot - Won't start anymore

hey there, just got home and checked the switch. Nothing. it's not wired at all. Where would the "control box" be? engine or boat side? where? It was running just fine before this... just shut off out of nowhere... I have crank. how can i check for spark or power before the plugs???

 

[Dukedog]

Re: Troubleshoot - Won't start anymore

Control box is usually tha "shifter" box unless tha "box" part has gone away and it has just tha shifter mounted. Is tha key switch mounted in tha dash or anywhere AWAY from tha shifter? Your motor has a later model harness on tha motor. It orginally had tha harness from tha boat hard wired to tha motor. So without being there ta check its no tellin' how its wired. Sounds like they took tha kill switch outta tha circuit. Do you have a manual? Do you know what tha switch boxes are?....................

 

["G"]

Re: Troubleshoot - Won't start anymore

Your manual for this engine will go through a complete process of "what to check" (like battery must be charged up and connected correctly) etc...

My 95 Merc 115 did what you are talking about... ran just fine then it just up and quit. Mine had stator issues. I replaced the stator and it's golden. The newer Mercs were noted for that problem as I understand.

The 1977 150 in line Merc has electronic ignition but It's been too many years since I've worked on that model to tell you what to look for. Your manual will have ohm readings and check point voltages. Could be as simple as a rectifier went bad. As you learn more about the ignition process you will find the problem.

Remember to ALWAYS start your diagnosis with a compression check. Finding you have a dead cylinder AFTER you put several hundred dollars into it is frustrating.

Good luck...

 

[Dukedog]

Re: Troubleshoot - Won't start anymore

John or G will hafta finish this. We are fixin' ta



START THA PARTY...........D